Grinding mill



June 15 1926.

K. MIDDELBOE GRINDING MILL Filed August 6, 1925 I VE/VTOR WIM",

Patented June 15, 1926.

UNITED STATES 1,589,302 PATENT OFFICE.

KRIS'IIAN IIInnnLBon. on FREDERIKSBERG, COPENHAGEN, DENMARK, ASSIGNOR T0 121.. SMIDTH & 00., on NEW YORK, 11. Y., A CORPORATION on NEW JERSEY.

GRINDING MILL.

Application filed August 6, 1925, Serial No. 48,506, and in Sweden August 2 1, 1924.

This invention relates to grinding mills of the general character of that shown in Letters Patent of the United States No. 1,499,624, dated July 1, 192%, in which the grinding bodies revolve about a vertical axis, between'an outer grinding ring and an I inner, sectional grinding ring, each section of the inner grinding ring being urged out- I wardly by springs. In the grinding mill shown in said Letters Patent,- the lines'of division between the sections of the inner grinding ring were parallel with the axis of' the milland it has beenfound, notwith standing the precautions taken to prevent it, that the grinding bodies are somewhat subject to shock as they roll from one section to another'across a line of division parallel with the axis. One object of the present invention has been, therefore, to modify the con struction of'the inner sectional grinding ring with respect to the lines of division between the sections, so that the subjection of the grinding bodies to shocksshall be avoided, the lines of division between the sections being made to overlap in the direction of rotation so that, at the times when the grinding bodies pass such lines of division, they are in contact with both the preceding and the following sections. Another object of the invention is to improve the means for supporting the grinding bodies in revolution. The invention will be more fully eX- plained hereinafter with reference to the accompanying drawings in which it is illustrated and in which:

Figure 1 is a view in vertical section, in the plane of the operating shaft, of the improved mill.

Figure 2 is a partial View of the same inhorizontal' section on the plane indicated by the broken line 2-2 of Figure 1.

Figures 3, at, 5, 6 and 7 are detail views illustrating different forms of construction, as to the overlapping divisional lines, of the sections of the driving ring.

In the construction shown, the vertical operating shaft a, driven by any convenient means, has keyed thereto a sleeve 6, which has radial arms or webs If. The inner grinding ring 0, formed in successive sections is urged outwardly, as to each section, by a spring (5, preferably looped as shown, which is interposed between each section and the corrresponding radial arm or web 6 The grinding bodies 6, preferably supported as hereinafter described, coact with the in? ner, sectional grinding ring a and the outer, relatively fixed grinding ring 'g, which is suitably mounted within the casing f; p

The material to be ground in the mill is introduced through a pipe p, falls upon the upper flange [1 of the sleeve 6, is thrown therefrom to the space between the two grinding rings, is subjected there to the ace tion of the grinding bodies 6, and falls up on a disc [2 which secured to the sleeve 6, and is thrown oii at its edge where it is caught by the upwardly moving current of air as described in the Letters Patent above mentioned. v

In the machine described in said Letters Iatent, the lines of division between successive sections of the inner grinding ring were parallel with the axis of the mill, withthe result that as each roller passed over such line of division it was subject to some shock. It has been found that such shock can be avoided and greater smoothness inthe oper ation of the mill can be secured by forming the adjacent edges of the sections of the inner grinding ring so that they shall overlap in the direction of rotation. As shown in Figure 3, the edgesc of the section a are diagonal to the plane of rotation. These might be arranged as shown in'Figure 3, or as shown at 0 in Figure 4, in which they are fish tailed. In Figure 5, they are shown as tongued and recessed on straight lines, as at 0. In Figure 6, they are shown as tongued and recessed on curved lines, as at 0 In Figure 7, the sections c are shown as arranged in'multiple and staggered. In all of these forms the result secured is the same, namely, that at the time when each roller passes a division between two successive ring sections it is in contact with both sections so that both sections yield together and no shock is imparted to the grinding body or roller.

It has been found also that desirable results are secured by supporting each roller or grinding body in the line of its axis and at a point above its mid horizontal plane, each roller or grinding body being thus hung or suspended from such point to permit free movement of such body with respect to its support. As shown in Figure 1 of the drawings, each roller or grinding body 6 is formed as a cylinder, closed at its upper end and resting upon a rod IL, which in turn is supported at its lower end by a corresponding arm of a spider hi which is secured to the sleeve Z). The bearings of the rod hat each end. are preferably spherical so as to permit free but limited movement of the grinding body in adapting itself to the operation of the mill, caps la? and if being provided for the purpose of limiting somewhat the displacement of the rods h. It is found in operation not only that the grinding bodies are thus properly supported in verticil relation with the inner and outer grinding rings, but tend at all times to maintain a parallel relation with the grinding rings, returning i immediately to such relation if they are deflected slightly by the material operated on.

I claim as my invention:

1. In a grinding mill, the combination of an outer grinding ring, an inner grinding ring. and cylindrical grinding bodies supported between the two grinding rings. the adjacent ends of successive sections 01" the inner grinding ring being overlapped in the direction of rotation.

2. In a grinding mill, the combination of an outer grinding ring, an inner grinding ring, cylindrical bodies between two grinding rings, and means to support each grinding body at a single point in its axis to permit free movement of such body with respect to its support.

'3. In a grinding mill, the combination of? grinding body at a single point in its axis and above its mid horizontal plane to permit free movement of such body with respect to its support.

4-. In a grinding mill, the combination of an outer grinding ring, an inner grinding ring, cylindrical grinding bodies between the grinding rings, each being hollow and closed at its upper end, a spider rotating with the inner grinding ring. and rods supported at one end on the arms of the spider and at their other ends engaging the closed ends of the grinding bodies to support the same at points in line with their axes above the mid horizontal plane to permit free movement of such bodies wit-h respect to their support.

5. In a grinding mill, the combination of an outer grinding ringan inner grinding ring cylindrical grinding bodies between the grinding rings, each being hollow and closed at its upper end a spider rotating with the inner grinding ring, and rods mounted for universal movement at one end on the arms of the spider and likewise mounting the grinding bodies at their other ends.

This specification signed this 21st day of July A. D. 1925.

KRISTIAN HIDDELBOE. 

